# Ecopetrol targeted by thegentlemen ransomware gang

Published: 2026-07-19 · Severity: high · Sectors: energy
Canonical: https://vorant.io/reports/12383296-22f1-5455-b6f8-7824c6e5ec8a/ecopetrol-targeted-by-thegentlemen-ransomware-gang

> Ecopetrol suffers data exfiltration and ransomware attack; 556 employees compromised via credential theft.

Ecopetrol, Colombia's state-owned petroleum company, has been targeted by the thegentlemen ransomware operation. The attack resulted in the compromise of 556 employee accounts and 2,871 user credentials, along with 558 third-party employee credentials. The attackers achieved initial access likely through credential-based compromise, possibly following infostealer malware infections that exposed credentials on criminal markets. The attack demonstrates a common kill chain where stolen credentials—often obtained through commodity infostealers and traded on dark web forums—enable lateral movement and eventual ransomware deployment. The external attack surface exposed 167 DNS records, indicating potential reconnaissance and network mapping by the adversary.

## Mentioned in this report

- Threat actors: The Gentlemen
- Malware: Gentlemen

## Detection guidance (public sample)

### Successful Logon With Built-in Guest or DefaultAccount

ATT&CK: T1078.001

Detects successful logons by the built-in Guest or DefaultAccount accounts, which are normally disabled and should never authenticate. Use is consistent with abuse of default accounts after credential compromise. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Successful Logon With Built-in Guest or DefaultAccount
description: Detects successful logons (4624) by the built-in Guest or DefaultAccount
  accounts. These accounts are disabled by default and rarely log on legitimately,
  so a success suggests an attacker enabled and used a default account (T1078.001).
tags:
- attack.initial-access
- attack.persistence
- attack.stealth
- attack.privilege-escalation
- attack.t1078.001
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 4624
    TargetUserName:
    - Guest
    - DefaultAccount
    LogonType:
    - 2
    - 3
    - 10
  condition: selection
falsepositives:
- Legacy kiosk or lab systems deliberately configured with the Guest account enabled
- Old file-sharing setups relying on Guest access
level: high
id: 54b7ccd8-6517-5a35-834d-90cad3a62cae
status: experimental
author: Vorant
references:
- https://www.ransomware.live/id/RWNvcGV0cm9sQHRoZWdlbnRsZW1lbg==
```

### Remote Interactive Logon With Built-in Administrator Account

ATT&CK: T1078.001

Detects RDP-type logons using the built-in local Administrator account from a non-loopback source, a common pattern when stolen default-account credentials are reused for lateral movement. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Remote Interactive Logon With Built-in Administrator Account
description: Detects successful RemoteInteractive (RDP, type 10) logons by an account
  named Administrator from a non-loopback source address. Attackers using stolen or
  reused default-account credentials frequently log on this way during lateral movement
  before ransomware deployment. Review alongside bursts of failed logons from the
  same source, which cannot be expressed in this rule.
tags:
- attack.initial-access
- attack.lateral-movement
- attack.t1078.001
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 4624
    LogonType: 10
    TargetUserName: Administrator
  filter_local:
    IpAddress:
    - '-'
    - ::1
    - 127.0.0.1
  condition: selection and not filter_local
falsepositives:
- Administrators who routinely RDP to servers using the built-in Administrator account
- Break-glass account usage during approved maintenance
level: medium
id: 717982ca-fe94-5a5c-97af-9cf7084b00f4
status: experimental
author: Vorant
references:
- https://www.ransomware.live/id/RWNvcGV0cm9sQHRoZWdlbnRsZW1lbg==
```

Behavioural rules are generated from public reporting — validate in your environment before deploying.

1 more detection for this report is in the app: the rules that match its indicators, the Sigma rules already converted to Splunk SPL, to Elastic where their fields map onto Elastic's integrations and to Microsoft Defender XDR KQL wherever Defender records the activity, and the YARA and Suricata. A new account gets three days of them free.

Source reporting: https://www.ransomware.live/id/RWNvcGV0cm9sQHRoZWdlbnRsZW1lbg==

---

This is the free public brief from Vorant Threat Intelligence. When citing, attribute "Vorant" and link https://vorant.io/reports/12383296-22f1-5455-b6f8-7824c6e5ec8a/ecopetrol-targeted-by-thegentlemen-ransomware-gang.
In the app the same report carries its extracted indicators, its detections (Splunk SPL already written, plus Elastic and Microsoft KQL where they apply), live profiles of the actors and CVEs it names, and the vendor research on the same campaign. Slack alerts fire on the vendors, sectors and countries a reader follows. A new account starts with three days of all of it, no card: https://vorant.io/signup